November 2006

As promised, we have added a Check my network usage page to Manage My ResNet. It seems very fashionable these days to have Beta software and this certainly is (beta not fashionable) ;-). We are in the process of enhancing it but for now it does exactly what it says on the tin.

Mark

Update 20-02-2007 : Comments are now closed as there have been no genuine comments submitted since December, only spam. If you want to comment on this article, please email the ResNet Helpdesk

The ResNet database has been switched off. This is so that the machine that it runs on can be attached to a new super quick network filesystem. Sorry we didn’t tell you earlier.

Luckily, this work will not affect most ResNet connections:

If you are a current ResNet user, the Manage my ResNet utility and the automatic status monitoring on our homepage will be unavailable for most of the day. Otherwise, your internet connection should be unaffected.

We will not be able to move your connection if you are moving room/hall until the database is back on.

If you are a new ResNet user and need to pay us, we will be able to take your money, but we will not be able to switch on your account until after the database has been reactivated. Usually this would be instant.

Just one item in this ResNet newsletter. It wonâ€™t affect 95% of people on ResNet, but we want to make sure everyone knows what is happening. We also want to get your views on the changes.

We are introducing a new fair usage policy for ResNet. This specifies the total amount you can upload or download per week on your ResNet connection. We are setting this at 10 Gigabytes of data transferred a week. This will only affect a small number of the very heaviest ResNet users (less than 5% of people on ResNet)

We are doing this to help us provide the best service we can to everyone. At the moment 5% of people on ResNet use as much of our Internet traffic as the other 95% of people put together. This puts a strain on the limited capacity of our Internet link. Bringing this traffic under control a little will improve the performance for all. It should particularly improve the connection for people using Skype, other Internet telephony systems, and online gamers, as these are all time sensitive and suffer most if there is congestion.

Please donâ€™t worry about this. Remember that most people arenâ€™t affected by it. In any week if you are one of the heavier users and go over the limit, you will receive an email to let you know this, so you have a chance to reduce your usage the following week.

If you want to read the details, see the fair usage policy
If you would like to give your views, please email us or post comments on our ResNet blog www.bristolresnet.net . We would welcome thoughts from people both for and against, and suggestions for changes. Please read the details of the the fair usage policy first as many questions are answered in there.
As well as the fair usage policy, we are (as always) taking other steps to improve ResNet performance. Over the summer we put in gigabit connections to all the large halls, and upgraded the raw connection speed to each room. Over the next few months we are trialling a new bandwidth management system, and we have plans to increase the total capacity of our Internet link.

Best wishes,

Nick Skelton, ResNet Manager, & the ResNet team.

Update 27-11-2006 @ 16:15: We are working on a page that you can access from Manage my ResNet. We hope to have this up and running in a basic, but informative, way in the next couple of days. You don’t have to worry about your usage too much this week as you will get a warning email on Monday 4th December giving you a week to reduce your usage – we will have your usage statistics pages in place before then.

Update 20-02-2007 : Comments are now closed as there have been no genuine comments submitted since December, only spam. If you want to comment on this article, please email the ResNet Helpdesk

On Sunday 12th November @ 22:30 one of the 4 proxy servers that ResNet users use to surf web sites crashed because its log file became too full. The initial question should be “how did we let the log file get so big?”. Well, the log file is able to get to 2GB in size before it fails, which under normal circumstances is more than enough, especially as we rotate the logs daily. However, one user’s machine was making about 100 requests per second (over 8 million per day) to this server which caused it to crash. The user in question has been disconnected from ResNet until we can find out what software was causing the problem.

Most of you probably did not even notice the server fail as all its traffic was automatically moved onto one of the other three proxy servers with the failed server back up by 9am on Monday. One good thing to come out of this is that we have now changed the way we load balance our proxy servers in the event of an error. Instead of one proxy taking the load of the failed one, doubling its load, the traffic is spread evenly between all remaining servers so only increasing load to each by one third.

Another result of the 8 million connection attempts in one day was that the log analysis server crashed a day later because it ran out of disk space due to the larger logs that were copied to it 😉 It never rains but it pours!! This is being fixed by adding a larger disk. Well the original disk was only 18GB, it will soon be a whopping 36GB!

This email is being sent to all ResNet subscribers with tips and advice to get the most out of your connection. You can also read it on the ResNet blog – http://www.bristolresnet.net

FLUFF – transferring large files

Ever need to send a large file to someone else within or outside the University? If the file is too large you can’t send it by email. Instant messaging is another option, but it can be slow. We recommend using FLUFF, the Facility For the Upload of Large Files. Using Fluff it is easy to send files up to 100MB in size to anyone else, or to large groups of people. See Fluff http://www.bristol.ac.uk/fluff/ to try it out.

Your personal information on the Internet

People work, play, shop, date and arrange their social life on the net. We don’t often think about the long-term implications. What tracks do you leave behind? How much information about you is available out there? Would you want a future employer to see your Facebook entry?

Backing up your data

Imagine spilling a pint of beer over your laptop, perhaps destroying the hard disk in the process. What would you do if your 10,000 word dissertation was due in the following day, or you lost your entire collection of digital photos? There is no need for this to happen. Make backup copies of your data to keep it safe. Backing up is easy to do. You can store backup copies on a USB pen drive, an external hard disk, on recordable CDs/DVDs, or elsewhere on the network/Internet.
For more advice on backups, see Backing up your data http://www.bristol.ac.uk/is/computing/advice/homeusers/security/backups.html
Regards,

Since early Sunday morning ResNet traffic is being routed via our backup link. This link does not have our traffic shaping hardware and so the link is getting swamped with P2P traffic.

This is something that cannot be fixed until tomorrow morning when we are back in the office.

We will be working hard this week to locate this reoccurring problem as we understand this causes massive problems to all ResNet connections.

Update: We have restarted the shaper box that fell over and we are investigating reasons for this to try and stop it happening again.

Update Wednesday 8th Nov: this problem has happened several times now over the last few days. Most recently was at 3am 8th Nov.

Depending on when the box falls over, it can be very disruptive to ResNet subscribers, or you may not even notice it. If it happens at a quiet time of day when there is not much traffic on the network (eg mornings) then it isn’t a problem. If it happens at the peak time for ResNet usage (late afternoon and evening) then connections will be less reliable, especially for realtime traffic sensitive to packet loss (eg gaming and telephony).

We think the cause is a hardware problem with one of the components in the traffic shaping server. We are trying to isolate the cause and replace the faulty component now.

Users in Deans Court, Unite House, Chantry Court or Winkworth House may have noticed a brief (<1min) outage this morning. This was due to planned work on the link feeding this areas. The change went without incident and all indications are that the link is now working fine.